organic chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clay ...

, an acetonide is the functional group composed of the cyclic ketal of a diol with

acetone Acetone (2-propanone or dimethyl ketone), is an organic compound with the formula . It is the simplest and smallest ketone (). It is a colorless, highly volatile and flammable liquid with a characteristic pungent odour. Acetone is miscible wi ...

. The more systematic name for this structure is an isopropylidene ketal. Acetonide is a common protecting group for 1,2- and 1,3- diols. The protecting group can be removed by

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis ...

of the ketal using dilute aqueous acid.

Example

The acetonides of small di- and triols, as well as many sugars and

sugar alcohol Sugar alcohols (also called polyhydric alcohols, polyalcohols, alditols or glycitols) are organic compounds, typically derived from sugars, containing one hydroxyl group (–OH) attached to each carbon atom. They are white, water-soluble solid ...

s, are common. The hexaol

mannitol Mannitol is a type of sugar alcohol used as a sweetener and medication. It is used as a low calorie sweetener as it is poorly absorbed by the intestines. As a medication, it is used to decrease pressure in the eyes, as in glaucoma, and to low ...

reacts with 2,2-dimethoxypropane to give the bis-acetonide, which oxidizes to give the acetonide of glyceraldehyde: :(CHOHCHOHCH₂OH)₂ + 2 (MeO)₂CMe₂ → (CHOHCHCH₂O₂CMe₂)₂ + 4 MeOH :(CHOHCHOCH₂OCMe₂)₂ + → 2 OCHCHCH₂O₂CMe₂ + H₂O An example of its use as a protecting group in a complex organic synthesis is the Nicolaou Taxol total synthesis. It is a common protecting group for sugars and sugar alcohols, a simple example being

solketal Solketal is a protected form of glycerol with an isopropylidene acetal group joining two neighboring hydroxyl groups. Solketal contains a chiral center on the center carbon of the glycerol backbone, and so can be purchased as either the racemate ...

. The acetonides of

corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are in ...

are used in

dermatology Dermatology is the branch of medicine dealing with the skin.''Random House Webster's Unabridged Dictionary.'' Random House, Inc. 2001. Page 537. . It is a speciality with both medical and surgical aspects. A List of dermatologists, dermatologist ...

, because their increased lipophilicity leads to better penetration into the skin. *

Fluclorolone acetonide Fluclorolone acetonide ( INN, or flucloronide, USAN, trade names Cutanit, Topicon) is a corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues ...

* Fluocinolone acetonide * Triamcinolone acetonide

References

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Example

See also

References